qgis - Buffer points by buffer amount in attribute value

I have a set of points in a shapefile with a real number attribute 'r' containing a radius (cp. screenshot below) and I would like to buffer these with amount of 'r'. As the result I expect a polygon shapefile with approximated circles of various radius, but the resulting shapefile is empty.

What am I missing?

(I must miss something, because it seems impossible to me that such a basic operation does not work in such a great software, and furthermore this feature has already been mentioned in the 1.8. doku: "Variations in buffering: buffer distance or buffer size can vary according to numerical values provided in the vector layer attribute table for each feature." http://docs.qgis.org/1.8/de/docs/gentle_gis_introduction/09_vector_spatial_analysis_buffers.html)

My project CRS is EPSG:25832, point shapefile the same. QGIS version is 2.8.7LTR (but same symptom in 2.14.3.)

This is what my points look like:

This is how I configure the buffer tool (German GUI):

And this is the result (None):

Answer

I would suggest opening a bug report. In the mean time, try performing the buffer using the QGIS Geoalgorithms -> Vector geometry tools -> Fixed distance buffer in the processing toolbox, or from some other provider/plugin.